science

Scleritis

Scleritis is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Scleritis rather than just read about it. In short: Scleritis is a serious inflammatory disease that affects the white outer coating of the eye, known as the sclera. The disease is often contracted through association with other diseases of the body, such as granulomatosis with polyangiitis or rheumatoid arthritis.

Key takeaways

Scleritis belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Scleritis to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Scleritis from memory before moving on to harder problems.

Reference excerpt

Scleritis is a serious inflammatory disease that affects the white outer coating of the eye, known as the sclera. The disease is often contracted through association with other diseases of the body, such as granulomatosis with polyangiitis or rheumatoid arthritis. There are three types of scleritis: diffuse scleritis (the most common), nodular scleritis, and necrotizing scleritis (the most severe). Scleritis may be the first symptom of onset of connective tissue disease. Episcleritis is inflammation of the episclera, a less serious condition that seldom develops into scleritis.

Signs and symptoms

Symptoms of scleritis include:

Redness of the sclera and conjunctiva, sometimes changing to a purple hue Severe ocular pain, which may radiate to the temple or jaw. The pain is often described as deep or boring. Photophobia and tearing Decrease in visual acuity, possibly leading to blindness The pain of episcleritis is less severe than in scleritis. In hyperemia, there is a visible increase in the blood flow to the sclera (hyperaemia), which accounts for the redness of the eye. Unlike in conjunctivitis, this redness will not move with gentle pressure to the conjunctiva.

Complications Secondary keratitis or uveitis may occur with scleritis. The most severe complications are associated with necrotizing scleritis.

Pathophysiology Most of the time, scleritis is not caused by an infectious agent. Histopathological changes are that of a chronic granulomatous disorder, characterized by fibrinoid necrosis, infiltration by polymorphonuclear cells, lymphocytes, plasma cells and macrophages. The granuloma is surrounded by multinucleated epitheloid giant cells and new vessels, some of which may show evidence of vasculitis.

Diagnosis Scleritis is best detected by examining the sclera in daylight; retracting the lids helps determine the extent of involvement. Other aspects of the eye exam (i.e. visual acuity testing, slit lamp examination, etc.) may be normal. Scleritis may be differentiated from episcleritis by using phenylephrine eye drops, which causes blanching of the blood vessels in episcleritis, but not in scleritis. Ancillary tests CT scans, MRIs, and ultrasonographies can be helpful, but do not replace the physical examination.

Classification Scleritis can be classified as anterior scleritis and posterior scleritis. Anterior scleritis is the most common variety, accounting for about 98% of the cases. It is of two types : Non-necrotising and necrotising. Non-necrotising scleritis is the most common, and is further classified into diffuse and nodular type based on morphology. Necrotising scleritis accounts for 13% of the cases. It can occur with or without inflammation.

Treatment

Medical In mild to moderate cases of scleritis, non-steroidal anti-inflammatory drugs (NSAIDs) such as flurbiprofen, indomethacin or ibuprofen may be prescribed for pain relief. Systemic corticosteroids like prednisolone may be used if NSAIDs are inappropriate or scleritis is posterior or necrotizing. Periocular steroid injections may be used in non-necrotizing scleritis but are contraindicated in necrotizing disease. If disease control is inadequate with steroids alone, immunosuppressives (e.g., cyclophosphamide, azathioprine, and methotrexate) and/or immunomodulators may be considered for treatment. In infective scleritis, if the infective agent is identified, topical or systemic antibiotics may be prescribed.

Surgical intervention Surgery may be indicated if scleral perforation or excessive scleral thinning is present. Bandage contact lens or corneal glue may be used to repair damaged corneal tissue in the eye and preserve the patient's vision. If not treated, scleritis can cause blindness.

Epidemiology Scleritis is not a common disease, although the exact prevalence and incidence are unknown. It is somewhat more common in women, and is most common in the fourth to sixth decades of life.

References

Rosenbaum JT. The Eye and rheumatic diseases. In: Firestein GS, Budd RC, Harris ED Jr, et al., eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 46. Watson P. Diseases of the sclera and episclera. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 15th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2009:chap 23.

External links

Illustrations

Worked examples

Example 1 — a first encounter with Scleritis

Start with the simplest possible case. Write down what Scleritis claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Scleritis before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Scleritis ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Scleritis

In research: Scleritis appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Scleritis in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Scleritis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Disorders of sclera and cornea, Inflammations, Steroid-responsive inflammatory conditions, so understanding it makes those chapters shorter.
In everyday life: Look for Scleritis outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Scleritis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Scleritis means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Scleritis out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Scleritis in simple terms?

Why does Scleritis matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Scleritis?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Scleritis.